1. Field of the Invention
The present invention relates to hollow polymer particles, an aqueous dispersion thereof and a production process thereof.
2. Description of the Background Art
Since hollow polymer particles composed of a highly crosslinked polymer have excellent heat resistance and solvent resistance as their properties and exhibit high coating property and shielding property, they are useful as white pigments for inks and also as light-scattering materials for light-scattering sheets.
Various processes have heretofore been known as production processes of hollow polymer particles composed of a crosslinked polymer (see, for example, Japanese Patent Application Laid-Open No. 127336/1987).
According to these processes, however, the resulting hollow polymer particles have involved problems that they become wide in particle diameter distribution, the degree of whiteness thereof becomes low because non-hollow particles of a small diameter coexist in a high proportion, and a high light-scattering ability cannot be obtained. In addition, they have also involved a problem that when they are used as a component of an ink, the resulting ink becomes easy to cause clogging because coarse particles coexist.